In the United States, heart failure (HF) is the most common hospital discharge diagnosis among older adults. About 40 percent of patients are readmitted within 1-year following their first admission for HF and hospitalization accounts for approximately 70 percent of the costs of HF management. Previous research shows that case management and telephonic support are effective in reducing HF hospitalizations, but these strategies are costly. As a result, the management of HF patients is evolving from the traditional model of face-to-face follow-up visits toward a proactive real-time technological model of assisting patients with monitoring and self- management while in the community. While several HF studies have implemented technologically-driven disease management programs, results have been mixed. These systems are effective for delivering the monitoring data and alerts to healthcare providers, but they have not been tested for their effectiveness in delivering and modifying patient behavior. This represents a significant gap in knowledge that unless filled will stifle the advancement of self-management science. Therefore, there is a critical need for the development of technologies that effortlessly increase self-monitoring performed by the patient (active monitoring) and monitoring done by external devices (passive monitoring), identify pre-clinical and clinical measurements of worsening HF, and deliver behavioral interventions that promote self-management with an overall goal of reducing HF hospitalizations. The proposed project will determine the impact of a self-monitoring mobile application on self-management, quality of life and hospital admission in ambulatory HF patients, determine the extent to which passive pre- clinical measurements predict symptoms of clinical worsening in HF and develop a notification message system for the mobile application to improve self-management of HF via patient participant feedback. These data will be crucial in further refining our intervention (the mobile application) and serve as the basis for future research that will test the mobile applicatio with a robust push notification system against the usual care in a larger randomized clinical trial This technological approach has positive implications in improving self-management and reducing disease morbidity. It will also foster the introduction of a novel tool and technology tha has the potential to bring about a new paradigm for self-management of common and debilitating chronic health conditions.